Pressure differential expanding means for well packers



a- .1969 c. a. COCHRAN 3,459,261

PRESSURE DIFFERENTIAL EXPANDING MEANS FOR WELL PQCKERS Filed Dec. 13,1965 3 Sheets-Sheet 1 lji v ,4

Aug. 5, 1969 c. B. COCHRA N 3,459,251

I PRESSURE DIFFERENTIAL EXPANDING MEANS FOR WELL PAcKsRs FiledDec.13,.1965 3 Sheets-Sheet 2 cuuamsy (0mm \fi INVENTOR.

l 4BY 6 W I ORNEy 5, 1969 4 c. a. COCHRAN 3,459,261

PRESSURE DIFFERENTIAL EXPANDING MEANS FOR WELL PACKERS Filed Dec. 13,1965 3 Sheets-Sheet 3 CHUDL 5/6 5 (We/IRAN 4 I N VEN TOR.

' z lw/w A TTORNE/S United States Patent Oflice 3,459,261 PRESSUREDIFFERENTlAL EXPANDING MEANS FOR WELL PACKERS Chudleigh B. Cochran,Houston, Tex., assignor to Brown Oil Tools, Inc., Houston, Tex., acorporation of Texas Filed Dec. 13, 12965, Ser. No. 513,465 Int. Cl.E21b 33/126 US. Cl. 166-120 1 Claim ABSTRACT OF THE DISCLOSURE A wellpacker including a packing element mounted on a slidable sleeve betweenabutments with the sleeve being responsive to pressure differentialsfrom both directions to increase the endwise compression on the packingelement.

The present invention relates to new and useful improvements in wellpackers.

In the past, well packers which have been exposed to very high-pressuredifferentials across the packing element have had a tendency to leak. Itis believed that this leakage results from the fact that the highpressures exceed the compression of the packing element and can,thereby, form a fluid pressure wedge between the packing element and theinterior of the pipe against which the packing element seals.

The present invention provides a well packer having a pressureresponsive means to increase the compressive load on the packing elementresponsive to a pressure differential across the packing element.

It is, therefore, an object of the present invention to provide animproved well packer in which pressure differentials held by the packingelement are utilized to increase the longitudinal compression of thepacking element to maintain the seal of the packing element.

Another object is to provide an improved well packer which will not leakunder conditions of very high-pressure differential.

Still another object is to provide an improved well packer utilizing thepressure differentials across the packing element to increase thecompression forces applied to the packing element and thereby avoid theaforementioned high-pressure leakage.

A further object is to provide a well packer with a pressure-responsivemeans to multiply the pressure forces on the packing element and therebyenable the packing element to remain sealed at very high-pressuredifferential.

The construction designed to carry out the invention will be hereinafterdescribed, together with other features thereof.

The invention will be more rapidly understood from a reading of thefollowing specification and by reference to the accompanying drawingsforming a part thereof, wherein an example of the invention is shown,and wherein:

FIGURE 1 is a partial sectional view illustrating the well packer of thepresent invention with the various parts of the packer being shown inthe position for lowering the apparatus within a well bore;

FIGURE 2 is a similar view illustrating the well packer in set position;

FIGURE 3 is a view of the well packer in set position when exposed topressure differentials from below the packing element;

FIGURE 4 is a similar view of the well packer in set position andexposed to pressure differentials from above; and

FIGURE 5 is another similar view of the well packer illustrating itsreleased position.

Referring to FIGURE 1, the well packer of the present invention is shownin its running-in position as it is being 3,459,261 Patented Aug. 5,1969 lowered on the tubing string T within the Well casing C. The wellpacker includes the tubular support or mandrel 10 on which the upperabutment 12 and the lower abut ment 14 are mounted with the anchoringassembly A, packing assembly P and the setting assembly S also mountedthereon between said abutments. The tubular support 10 is connected tothe tubing string T by collar 16. The connecting threads 18 between thetubular support 10 and the collar 16 provide the releasing means for thepacker and are special threads, preferably a left-hand, lowfriction-type of threads to assure operation of the release function ofsuch connection, as hereinafter set forth.

The upper abutment 12 includes the ring 20 having an inwardly projectingflange 22 which closely surrounds the exterior of the collar 16. Thelower end of the collar projects outwardly to provide the upwardlyfacing shoulder 24. Bearing rings 26 are positioned around the collar 16between its upwardly facing shoulder 24 and the flange 22 on the ring 20to limit the friction during release. The main abutment body 28 isthreadedly secured to the ring 20 with the locking ring 30 and thebearing ring 32 positioned to maintain the aforementioned components ofthe upper abutment in fixed relation longitudinally with respect to thecollar 16 while allowing relative rotation of the collar 16 with respectto the upper abutment. The body 28 surrounds the tubular support 10 andis spaced therefrom to provide a recess surrounding the tubular support10 for movement of part of the packing assembly therein.

The packing assembly P is mounted on tubular support 10 immediatelybelow the upper abutment 12. It includes the upper packing follower 34,the lower packing follower 36, the plastic packing element 38, allmounted in surrounding relationship to the pressure-responsive means orpacking sleeve 40 and between the engaging means or outwardly projectingupper and lower flanges 42 and 44 on the sleeve 40. Additionally, theupper follower 34 is interengaged with the upper abutment 12 byconnecting means which includes the interengaging flanges 46 and 48. Theflange 48 is spaced a greater distance from the body 28 of the upperabutment than the thickness of the flange 46, and the flange 46 isspaced from the remainder of the follower 34 by a greater distance thanthe thickness of the flange 48 to allow move-ment of follower 34relative to body 28. Additionally, the upper end of the follower 34 isprovided with the slot 50 to allow pressure to be exerted over thisportion of the follower 34. The packing sleeve 40 is generally tubularin shape and provided with sealing means, such as packing ring 52, whichseals between the interior of the packing sleeve 40 and the exterior ofthe mandrel 10 at a position below the snap ring 54. The snap ring 54 ispositioned in a groove around the exterior of mandrel 10 but does notengage the interior surface of the packing sleeve 40 so that the packingsleeve 40 is free to move longitudinally with respect to the mandrel 10and the upper abutment 12.

The anchoring assembly A is interconnected with the packing assembly Pby a connecting means which includes the flange 56 on the lower packingfollower 36 and the flange 58 on the upper anchoring expander 60. Theflange 58 is spaced from the upper end of the expander 60, and flange 56is spaced from follower 36 to provide a distance in which the follower36 may move with respect to the upper expander 60. Additionally, thelower end of the follower 36 is provided with the slot 57 to allowpressure to be exerted against the lower side of follower 36.

The anchoring assembly is positioning around tubular support 10immediately below the packing assembly P. The anchoring assembly Aincludes the upper and lower expanders 60 and 62 and the grippingelements 64. The gripping elements 64 are made in two sections with theusual T connection 66 therebetween. The upper gripping sections are eachprovided with a pin 68 which extends therethrough into a slot 70 inexpander 60. Additionally, the lower sections of the gripping elements64 are each provided with a pin 72 which extends therethrough andprojects into a slot 74 in the lower expander 62. Each of the sectionsof the gripping elements 64 is provided with dove-tail projections 76 toengage in the dove-tail slots 78 in the respective expanders 60 and 62.The ex- 7 terior of the tubular support is provided with the snap ring80 positioned in a groove and extending outwardly therefrom. The snapring 80 is adapted, as hereinafter explained, to engage in the recess 82in the upper end of the lower expander member 62.

The setting means S illustrated for the packer is a pressure-responsivemeans. The fluid pressure is conducted to the pressure-responsive meansfrom the interior of the tubular support 10 through the port 84. Thepressureresponsive means includes the sleeve 86, the piston ring 88 andthe sealing ring 90. The sealing ring 90 immediately surrounds theexterior of the mandrel 10 and rests on the lower abutment 14 to providea seal between sleeve 86 and tubular support 10. In the running-inposition, the sleeve 86 is connected to the ring 90 by the shear pin 92and is connected to the lower expander 62 by the pin 94. Suitablesealing means is provided on the inner and outer surfaces of the piston88 and the ring 90 to contain the fluid pressure therebetween duringsetting.

A suitable locking means 96 is provided in the form of locking slipswhich are positioned under the tapered surface of the lower expander 62and have their toothed surface in engagement with the exterior of thetubular support 10. The lower end of the locking means 96 abuts theupper end of the piston 88. The teeth on the locking slips are directeddownwardly whereby the slips will have very little resistance to upwardmovement with respect to the tubular support 10 and will prevent adownward movement of the lower expander 62 with respect to the tubularsupport 10 to thereby assure that the setting means S when set will beheld in such set position.

The lower abutment 14 supports the ring 90 and includes the abutmentring 98 which is secured to the exterior of the tubular support 10 bythe snap rings 100 and 102. The seat 104 is provided in the lower end oftubular support 10 to receive the setting ball 106 or other suitabledevice for the setting operation of the well packer.

In operation, the well packer with the components positioned asillustrated in FIGURE 1 is lowered on the tubing string T into the wellcasing C to the position at which the well packer is to be set.Thereafter, the setting ball 106 is dropped through the tubing string Tand seats on the seat 104 in the lower end of the tubular support 10.With the setting :ball 106 in position, the tubing string T is pressuredup with a suitable fluid, normally hydraulic fluid. This fiuid pressureis conducted through the port 84 and urges the piston ring 88 upwardly.The initial movement of the piston ring 88 moves the locking slips 96upwardly until the upper surface of the piston ring 88 engages the lowersurface of the lower expander 62. Thereafter, when sufficient pressureis exerted against the piston ring 88 to shear the pin 92, the pistonring 88, the sleeve 86, the locking means 96 and the lower expander 62move upwardly as a unit. This upward movement is translated through theanchoring assembly A to compress the packing assembly P into setposition. The compression of the packing assembly P is accomplished bythe upward force exerted by the upper expander 60 against the lowerfollower 36, which force provides an end-wise compression of the packingelement 38 between the followers 34 and 36 with the upper abutment 12holding the follower 34 to cause the packing element 38 to expandradially outward into set position with the well casing C. The upperfollower 34 will be in abutting relation to the upper abutment 12 toprovide the resistance necessary to create the setting forces for thepacking assembly. Thereafter, continued upward movement of the piston 88moves the expander members 60 and 62 toward each other to thereby forcethe gripping element 64 outwardly into pipe-gripping position with thewall of the well casing C to complete the setting of the packer.

When the well packer is in set position and is exposed to large pressuredifferentials from beneath the packing element, the pressuredifferential is exerted on the lower end of the packing sleeve member 40and also on the lower side of the packing follower 36. This condition isillustrated in FIGURE 3. Since in set position room is provided forupward movement of both the sleeve 40 and the packing follower 36, thispressure is exerted on the total annular area between the exterior oftubular support 10 and the interior of well casing C to create a forcewhich further compresses the packing element 38. This pressure forcecreated is greater than the force of the pressure on the packing elementsince this pressure force results from pressure on the annular area ofthe sleeve and the annular area of the packing element.

Additionally, the same action occurs when the well packer is set and isexposed to high-pressure differentials from above. This condition isillustrated in FIGURE 4. Such pressure differential is transmittedthrough the port 108 in the abutment body 28. In this manner, the upperpressure is exerted on the total annular area between the exterior ofthe tubular support 10 and the interior of the casing C. The sleeve 40moves downwardly until its flange 42 engages the upper end of thefollower 34. Thereafter, the pressure force on the sleeve 40 istransmitted through the follower 34 to the packing element 38 to therebyincrease the setting force of the packing element 38.

This increase in setting force resulting from pressures both above andbelow over a larger area than the exposed area of the packing element 38creates a compressive force in the packing element which is sufiicientto prevent the aforementioned high-pressure leakage. In each case wherethe pressure differentials held by the packing assembly approach thepossible high-pressure leakage point of the packing element, suchpressure differentials are utilized to increase the setting load on thepackaging to assure the maintenance of the packing seal. Thus, thegreater the pressure load on the packing, the greater the setting forceon the packing will be multiplied to hold the packing sealed. Thismechanical advantage assures the maintenance of the seal at all times.

The release of the well packer is accomplished by rotation of the tubingstring T in a clock-wise or right-hand direction. This rotation actuatesthe threaded connection 18 to initially cause the tubular support 10 tomove down- Ward. Since a special threaded connection is used, therotation of the tubing string does not unthread any other connection andthereby assures that the release functions properly. As the tubularsupport 10 moves downwardly, the snap ring engages in the recess 82 toexert a downward force on the lower expander 62. The downward movementof the lower expander 62 retracts the lower section of the grippingelement 64 from engagement with the well casing C until the pin 72engages the upper end of the slot 74. Thereafter, further downwardmovement is prevented since the upper section of the gripping elementsis held in engagement with the well casing C. Further rotation of thetubing string causes the upper abutment 12 to be moved upward to relaxthe packing assembly P. The engagement of the flanges 46 and 48 and theengagement of the flange 42 with the upper surface of the upper follower34 raises the follower 34 and the sleeve 40 upward with the upwardmovement of the upper abutment 12. As soon as the flange 44 0f thesleeve 40 engages the lower side of the lower follower 36, the packingassembly P is completely released and sleeve 40 moves the follower 36upward until its flange 56 engages the flange 58 on the upper expander60. Continued upward movement of these elements withdraws the upperexpander 60 from under the upper section of the gripping element 64 tothereby complete the retraction of the gripping elements 64 and thusefiect complete release of the device. During release of the well packerassembly, the port 110 which extends through collar 16 is uncovered bythe downward movement of tubular support 10. The port 110 will allowfluid pressures above the packing element to be equalized through thetubular support during release and also during removal of the wellpacker from the well bore.

From the foregoing it can be seen that the well packer of the presentinvention provides an improved packing assembly which will maintain itsseal under extremely high-pressure differentials by utilizing suchpressure differentials over an annular area larger than the annular areaof the packing element to increase the setting force on the packingelement. This improved packing assembly structure assures that thepacking seal will be maintained under all pressure conditions.

The foregoing disclosure and description of the invention areillustrative and explanatory thereof and various changes in the size,shape and materials, as well as in the details of the illustratedconstruction, may be made within the scope of the appended claim withoutdeparting from the spirit of the invention.

I claim:

1. A well packer, comprising:

a tubular support,

an upper abutment and a lower abutment mounted in spaced relation onsaid tubular support,

an anchoring assembly on said tubular support support between saidabutments,

setting means on said tubular support and including:

means defining a pressure chamber surrounding said tubular support,

a pressure responsive piston slidably mounted around said tubularsupport in said pressure chamber, and

means for conducting pressure from the interior of said tubular supportto said pressure chamher,

said pressure responsive piston coacting with one of said abutmentswhereby movement of said piston responsive to pressure in said pressurechamber moves said packing assembly and said anchoring assembly to setposition, and

a packing assembly mounted on said tubular support between saidabutments and including:

a plastic packing element adapted when compressed to extend radiallyoutward into set position, and pressure responsive means mounted on saidtubular support and coacting with said packing element to exert acompressive force on said packing element responsive to a pressuredifferential held by said packing element, said pressure responsivemeans including:

a sleeve surrounding said tubular support and slidable thereonresponsive to pressure around said tubular support,

means sealing between said sleeve and said tubular support,

said packing element being mounted around said sleeve,

upper and lower packing followers mounted around said sleeve above andbelow said packing element,

means on said sleeve engaging said upper packing follower when saidsleeve is in its lower position,

means on said sleeve engaging said lower packing follower when saidsleeve is in its upper position,

a locking means coacting between said piston and said tubular support toallow setting movement of said piston with respect to said tubularsupport and to prevent reverse movement of said piston with respect tosaid tubular sup-port, and

means threadedly connecting the tubular support to the other of saidabutments whereby rotation of said tubular support increases the axialdistance between said abutments to release said anchoring assembly andsaid packing assembly from set position.

References Cited UNITED STATES PATENTS 3,180,419 4/1965 Cochran et a1166--12O 3,211,227 10/1965 Mott 166120 3,223,169 12/1965 Roark 166-1203,339,637 9/1967 Holden 166120 3,391,740 7/1968 Edwards 166-1203,394,762 7/1968 Young 166134 JAMES A. LEPPINK, Primary Examiner US. Cl.X.R. 166-131, 182

